1. Field of the Invention
The present invention relates to a speaker.
2. Description of Related Art
Japanese Patent Application Publication No. H04-313999 has disclosed a speaker, in which a magnetostrictive actuator is used to vibrate with a diaphragm, thereby obtaining an acoustic output sound. The magnetostrictive actuator is referred to as an actuator in which a magnetostrictive element whose form can alter by applying an external magnetic field thereto is used.
FIG. 1 shows a configuration of an acoustic output device 300 for outputting an acoustic sound. This acoustic output device 300 has a player 301, an amplifier 302, a magnetostrictive actuator 303, and a diaphragm 304. In this device 300, the magnetostrictive actuator 303 and the diaphragm 304 constitutes a speaker 305.
The player 301 reproduces, for example, an acoustic signal from a compact disc (CD), a mini disc (MD), a digital versatile disc (DVD) and outputs it. The amplifier 302 receives this acoustic signal from the player 301 and then, amplifies and supplies it to the magnetostrictive actuator 303. The magnetostrictive actuator 303 has a driving rod 303a for transmitting any displacement outputs. A tip of the driving rod 303a is attached to the diaphragm 304.
The magnetostrictive actuator 303 drives the diaphragm 304 based on the acoustic signal. In other words, the driving rod 303a of the magnetostrictive actuator 303 is displaced corresponding to a waveform of the acoustic signal, so that this displacement can be transmitted to the diaphragm 304. This enables the diaphragm 304 to output an acoustic sound corresponding to the acoustic signal.